APPLICATIONS OF TECHNOLOGY:
- Electron energy-loss spectroscopy
- Low energy electron microscopy
- Dynamic transmission electron microscopy
- Quantum information science
- Quantum electron microscopy
- Narrow energy distribution
- Higher accuracy in spectroscopy
- Reduced chromatic aberrations in microscopy
- Electron beams are used in imaging techniques like electron microscopy and spectroscopy and other sensor technologies. The further development of these technologies is however limited by the nature of current electron beam emitters which produce beams with broad energy distributions. The narrowest energy distribution currently available is from cold field emission guns, approaching 0.2 eV, which is still too broad a spread for emerging technologies like quantum electron microscopy or high-resolution vibrational spectroscopy.
Berkeley Lab researchers have developed a method to generate an electron beam with a narrow energy distribution, with a full-width-half-maximum spread as low as about 16 meV while remaining high brightness. This new method stands out as more than 10 times better than the best, currently available technology that applies monochromators to commercial field emitters to reduce the energy spread. They have the drawback of a dramatic reduction in the beam current from the filtering of the energy distribution, constraining the practical application of monochromators to a few niche areas.
Researchers accomplished this narrow energy distribution by fabricating a superconducting niobium nanotip field emitter that is cooled to about 5.9 K. The space at the apex creates distinct quantum energy states that can be tuned and cut off at the sharp low-temperature Fermi edge. As a result, this method produces an electron beam with a narrow energy distribution and a brightness among the highest currently available. This method is especially useful in low energy electron microscopy and electron energy-loss spectroscopy, the viability of which suffer from the broader energy distributions of current techniques.
DEVELOPMENT STAGE: Similar system validated in relevant environment
FOR MORE INFORMATION:
Research Highlight, Science, 379, 6628, 151 (2023)
- Alexander Stibor
- Cameron Johnson
STATUS: Patent pending.
OPPORTUNITIES: Available for licensing or collaborative research.